A BRIEF HISTORY OF

MICROBIOLOGY

THE FIRST OBSERVATIONS

• ROBERT HOOK

• FIRST TO SEE “CELLS” WHILE OBSERVING A THIN SLICE OF CORK

• MARKED THE BEGINNING OF THE CELL THEORY: THEORY THAT ALL LIVING THINGS ARE COMPOSED OF CELLS

• ANTON VAN LEEUWENHOEK

• FIRST TO OBSERVE LIVE ORGANISMS THROUGH A MICROSCOPE

• “ANIMALCULES”

THE DEBATE OVER SPONTANEOUS GENERATION• AT ONE TIME MANY BELIEVED THAT SOME FORMS OF LIFE

COULD ARISE SPONTANEOUSLY FROM NONLIVING MATTER (SPONTANEOUS GENERATION)

FRANCESCO REDI

NEEDHAM AND SPALLANZANI

Needham

Spallanzani

“Microbes developed

spontaneously from the fluids”

Needham responded: The “virtual force” necessary for spontaneous generation had been destroyed by the heat and was kept

out of the flasks by the seals.

THE THEORY OF BIOGENESIS

• RUDOLF VIRCHOW: CHALLENGED SPONTANEOUS GENERATION WITH BIOGENESIS (THE CONCEPT THAT LIVING CELLS CAN ARISE ONLY FROM PREEXISTING LIVING CELLS)

• ARGUMENTS CONTINUED UNTIL THE ISSUE WAS RESOLVED BY LOUIS PASTEUR

LOUIS PASTEUR

LOUIS PASTEUR•MICROORGANISMS CAN BE PRESENT IN NONLIVING

MATTER

•MICROBIAL LIFE CAN BE DESTROYED BY HEAT

•METHODS CAN BE DEVISED TO BLOCK THE ACCESS OF AIRBORNE MICROORGANISMS TO NUTRIENT ENVIRONMENTS

• FORM THE BASIS OF ASEPTIC TECHNIQUES

• PREVENT CONTAMINATION BY UNWANTED MICROORGANISMS

• ANY APPEARANCE OF “SPONTANEOUS” LIFE IN NONLIVING SOLUTIONS CAN BE ATTRIBUTED TO MICROORGANISMS THAT WERE ALREADY THERE

THE GOLDEN AGE OF

MICROBIOLOGY

ROBERT KOCH

• FIRST PROOF THAT BACTERIA CAUSE DISEASE

• ESTABLISHED A SEQUENCE OF EXPERIMENTAL STEPS FOR DIRECTLY RELATING A SPECIFIC MICROBE TO A SPECIFIC DISEASE: KOCH’S POSTULATES

FERMENTATION & PASTEURIZATION• PASTEUR FOUND THAT MICROORGANISMS CALLED

YEASTS CONVERT THE SUGARS IN ALCOHOL IN THE ABSENCE OF AIR (FERMENTATION)

• USED TO MAKE WINE AND BEER

• SOURING AND SPOILAGE ARE CAUSED BY BACTERIA. BACTERIA CHANGE THE ALCOHOL INTO VINEGAR (ACETIC ACID)

• PASTUER’S SOLUTION: HEAT THE BEER AND WINE JUST ENOUGH TO KILL MOST OF THE BACTERIA THAT CAUSED THE SPOILAGE (PASTEURIZATION)

THE GERM THEORY OF DISEASE

• IDEA THAT MICROORGANISMS CAUSE DISEASE

• AGOSTINO BASSI: MADE 1ST ASSOCIATION BETWEEN A MICROORGANISM AND A DISEASE BY PROVING THAT A FUNGUS WAS THE CAUSE OF A SILKWORM DISEASE

• PASTUER FOUND THAT ANOTHER SILKWORM DISEASE WAS CAUSED BY A PROTOZOAN

JOSEPH LISTER

• APPLIED GERM THEORY TO MEDICAL PROCEDURES

• BEGAN TREATING SURGICAL WOUNDS WITH A PHENOL SOLUTION (KNOWN TO KILL BACTERIA)

• REDUCED INFECTIONS AND DEATHS AND SOON ADOPTED BY OTHER SURGEONS

VACCINATION• EDWARD JENNER SHOWED THAT THE MILD DISEASE

COWPOX GAVE IMMUNITY TO SMALLPOX

• INOCULATED PEOPLE WITH COWPOX MATERIAL BY SCRATCHING THEIR ARM WITH A COWPOX-INFECTED NEEDLE

• BECAME KNOWN AS VACCINATION

• IMMUNITY: PROTECTION FROM DISEASE THAT VACCINATION PROVIDES

• PASTEUR THEN SHOWED WHY VACCINATIONS WORK

THE BIRTH OF MODERN CHEMOTHERAPY: DREAMS OF A MAGIC BULLET• CHEMOTHERAPY: TREATMENT OF DISEASE BY CHEMICAL

SUBSTANCES

• SYNTHETIC DRUGS: PREPARED FROM CHEMICALS IN A LABORATORY

• ANTIBIOTICS: PRODUCED NATURALLY BY BACTERIA AND FUNGI

• PAUL EHRLICH: SPECULATED ABOUT A “MAGIC BULLET” THAT WOULD DESTROY A PATHOGEN WITHOUT HARMING THE HOST

• FOUND SALVARSAN, AN ARSENIC DERIVATIVE THAT WAS EFFECTIVE AGAINST SYPHILIS

THE BIRTH OF MODERN CHEMOTHERAPY: DREAMS OF A MAGIC BULLET• FIRST ANTIBIOTIC DISCOVERED BY ACCIDENT

• ALEXANDER FLEMING OBSERVED THE INHIBITION OF BACTERIAL GROWTH BY THE MOLD Penicillium notatum.

• THE INHIBITOR (PENICILLIN) WAS MASS PRODUCED AND CLINICALLY TESTED IN THE 1940S.

MODERN DEVELOPMENTS IN MICROBIOLOGY

• BACTERIOLOGY: THE STUDY OF BACTERIA

• MYCOLOGY: THE STUDY OF FUNGI

• PARASITOLOGY: THE STUDY OF PROTOZOA AND PARASITIC WORMS

• IMMUNOLOGY: THE STUDY OF IMMUNITY

• VIROLOGY: THE STUDY OF VIRUSES

RECOMBINANT DNA TECHNOLOGY• GENETIC ENGINEERING

• BACTERIA PREFERRED BECAUSE OF THEIR SIMPLICITY AND RAPID REPRODUCTION RATE

• MICROORGANISMS CAN NOW BE GENETICALLY ENGINEERED TO MANUFACTURE LARGE AMOUNTS OF HUMAN HORMONES & OTHER MEDICAL SUBSTANCES

• FRAGMENTS OF HUMAN OR ANIMAL DNA CAN BE ATTACHED TO BACTERIAL DNA

• WHEN INSERTED INTO BACTERIA, IT CAN BE USED TO MAKE LARGE QUANTITIES OF THE DESIRED PROTEIN

Microbes &

Human Welfare

Recycling Vital

Elements (CO2, N)

Bio-remediation (clean

up pollutants

)

Insect Pest

Control

Sewage Treatment

MICROBES & HUMAN DISEASE• NORMAL MICROBIOTA (FLORA): THE MICROORGANISMS THAT

COLONIZE A HOST WITHOUT CAUSING DISEASE

• DO NOT HARM US….MAY BENEFIT US

• PREVENT GROWTH OF HARMFUL MICROBES

• PRODUCE USEFUL SUBSTANCES (VITAMINS)

• THE DISTINCTION BETWEEN HEALTH AND DISEASE IS PART OF A BALANCE BETWEEN THE NATURAL DEFENSES OF THE BODY AND THE DISEASE-PRODUCING PROPERTIES OF MICROORGANISMS

• DEPENDS ON OUR RESISTANCE (THE ABILITY TO WARD OFF DISEASES)

INFECTIOUS DISEASES

• PATHOGENS INVADE A SUSCEPTIBLE HOST AND CARRY OUT AT LEAST PART OF THEIR LIFE CYCLE IN THAT HOST

• EMERGING INFECTIOUS DISEASES: NEW OR CHANGING DISEASE THAT IS INCREASING OR HAS THE POTENTIAL TO INCREASE IN THE NEAR FUTURE